The vasodilation induced by nerve stimulation in exocrine glands-e.g., submandibular salivary gland (1), tongue (2), sweat glands (3), and nasal mucosa (4)-is largely atropine resistant, whereas secretion easily can be blocked by muscarinic antagonists. The occurrence of a subpopulation of vasodilatory nerves was first suggested, but later a kinin mechanism was suggested to be responsible for this vasodilation (5-9).
MATERIALS AND METHODSTen cats (body weight 2-4 kg) of both sexes were used for immunohistochemical studies. In two of these cats the superior cervical ganglion was excised unilaterally 14 days before they were killed. In four other cats vinblastine sulfate (Sigma) (1% in 0.9% NaCl) was locally applied to the submandibular and sphenopalatine ganglia and to pancreas 24 hr before perfusion with ice-cold 10% (vol/vol) formalin (21). These ganglia and parts of the submandibular gland, the nasal mucosa, tongue, lung, and pancreas were then processed for indirect immunohistochemical studies according to Coons (22) as described (see ref. 18) by use of a VIP antibody (5603-5; for detail about this antiserum, see refs. 23 and 24) and AcChoE staining (18,25,26). In some cases, immunohistochemical analysis for VIP and AcChoE staining were performed on the same section. Alternatively, adjacent sections were processed for the respective procedure. The latter approach was used because Triton X-100 (added to VIP antiserum to enhance penetration of antibodies) inactivated AcChoE (18,27). For details and validity of procedures and for controls, see ref. 18. Physiological experiments were done in 15 cats anesthetized with chloralose (50 mg/kg) plus urethane (100 mg/kg) intravenously. The trachea was cannulated. The blood pressure was recorded via a femoral artery. Rectal temperature was kept constant at 38°C. The submandibular gland, its duct, and nerve supply were exposed. The duct was cannulated with a polyethylene tube (PE 50) and salivation was measured with a drop recorder. The chorda-lingual nerve was cut, and the peripheral cut end was mounted to a bipolar platinum electrode. Preganglionic stimulation was performed with square wave pulses of either 2 or 15 Hz, 8 V, and a duration of 1 msec. To measure the venous outflow from the gland, we introduced a polyethylene catheter (PE 160) into the external jugular vein after all branches, except the one draining the submandibular gland, had been tied. Blood flow was measured by a drop recorder and blood was reinfused into the cephalic vein with a peristaltic pump. Heparin (1000 IU/kg) was given intravenously. The Abbreviations: VIP, vasoactive intestinal polypeptide; AcCho, acetylcholine; AcChoE, acetylcholinesterase. 1651The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact.
